1. Technical Field
The present invention relates to a liquid ejecting head and a liquid ejecting apparatus, and more particularly, to a liquid ejecting head and a liquid ejecting apparatus which is useful when applied to those employing a circulation type in which a liquid is circulated via each of pressure generation chambers between a first and second manifolds which are liquid storage sections arranged in both sides across a plurality of pressure generation chambers having nozzle openings and communicating with each of the pressure generation chambers.
2. Related Art
As a liquid ejecting apparatus, for example, there is provided an ink jet type recording apparatus including an ink jet type recording head (hereinafter, simply referred to as a recording head) which has a plurality of pressure generation chambers which generates a pressure with a pressure generation unit configured of a piezoelectric element to eject ink droplets, an ink supply path which supplies the ink individually from a common manifold to each of the pressure generation chambers and a nozzle opening which is formed in each of the pressure generation chambers and ejects ink droplets (see, for example, JP-A-2002-355961 and Japanese Patent No. 3097718).
In the ink jet type recording apparatus described above, the ink droplets are ejected from the nozzle opening to the outside and are landed on a predetermined position of a medium such as a paper by applying an ejection energy to the ink inside the pressure generation chamber, communicating with the nozzle opening corresponding to a printing signal.
Accordingly, in the recording head of the ink jet type recording apparatus of this type, the nozzle opening is exposed to the atmosphere. Thus, the ink is thickened by evaporation of moisture through the nozzle opening and it may cause adverse effect to ejection characteristics of the ink droplets. In other words, when even a portion of the ink is thickened, an ejection amount and an ejection speed of the ink droplets via the nozzle opening are changed, and a defect, in which variation of the landing occurs, is generated.
In order to avoid the defect described above, there has been studies such that the ink does not stay in the vicinity of the nozzle opening by circulating the ink in the pressure generation chamber communicating with the nozzle opening. In other words, the recording head of the circulation type described above is configured such that the liquid is circulated via each of the pressure generation chambers between the first and second manifolds which are the liquid storage sections disposed in both sides across a plurality of pressure generation chambers having nozzle openings and communicating with each of the pressure generation chambers.
However, in the recording head applying the circulation type described above, when the circulation amount of the ink is large, the flow of the ink inside the pressure generation chamber is fast and the ink is hardly ejected from the nozzle opening. As a result, there is a problem that stable ejection is disturbed. In addition, when the circulation amount is small, in particular, the number of the ejection nozzles is increased and when required ejection amount is increased, there is a problem that shortage of the ejection amount of the ink occurs. Thus, a study is required in order to simultaneously satisfy the two conflicting requirements.
In addition, such a problem exists similarly in the liquid ejecting head ejecting other liquids as well as the ink jet type recording head ejecting the ink.